The invention relates to photography and to cameras and more particularly relates to a camera assembly having forward and return cam surfaces for a turret on different parts.
Movable lens barrels commonly include cam surfaces in the form of slots or grooves or raised ribs. The cam surfaces are traveled by pins or other cam followers as the lens barrel is extended and retracted to move internal lens structures. U.S. Pat. No. 6,369,956 is an example of a zoom lens barrel in which grooves are followed by pawls of a movable component. U.S. Pat. No. 4,937,609 is an example of a camera lens, in which an optical element pivots in and out of the optical path in response to a cam follower following a non-uniform cam surface of an internal lens part.
U.S. Pat. Nos. 5,225,939 and 6,369,956 teach the use of guide surfaces on forwardly extending portions of a fixed support to guide linear movement of a lens component.
One-time-use cameras and reusable and inexpensive reusable cameras commonly use molded plastic parts to reduce costs. A practical limitation is the complexity of the parts and the resulting complexity and cost of required molds. U.S. Pat. No. 5,225,939 discloses a lens barrel having an integrally formed zoom lens tube of a very complex shape. The tube has an integrally formed rib that acts as a cam surface.
It would thus be desirable to provide an improved camera assembly in which cam surfaces are provided by relatively simple to mold parts.
The invention is defined by the claims. The invention, in broader aspects, provides a camera assembly having a support that defines an optical axis. The support has a forwardly extending cam finger. The cam finger has a first cam surface that is inclined relative to an imaginary line parallel to the optical axis. A guide has a forward rim that is spaced from the support. The support and guide are separate pieces that are joined together. The guide has a notch that receives the cam finger. The notch has a second cam surface that parallels and is spaced from the first cam surface. The cam surfaces together define a cam slot having first and second opposed ends. A lens barrel selectively translates along the optical axis between an inner position and an outer position relative to the support. The lens barrel has a cam follower that extends into the slot and is movable along the slot between the ends.
It is an advantageous effect of the invention that an improved camera assembly are provided in which a cam follower follows a cam surface formed on one part, when moved in a first direction, and follows another cam surface formed on a different part, when moved in a second, opposite direction.